Abstract: IRAS F11119+3257 is a quasar-dominated Ultra-Luminous InfraRed Galaxy, with a
partially obscured narrow-line seyfert 1 nucleus. In this paper, we present the
NIR spectroscopy of F11119+3257, in which we find unusual Paschen emission
lines, and metastable He I* $\lambda$10830 absorption associated with the
previously reported atomic sodium and molecular OH mini-BAL (Broad Absorption
Line) outflow. Photo-ionization diagnosis confirms previous findings that the
outflows are at kilo-parsec scales. Such large-scale outflows should produce
emission lines. We indeed find that high-ionization emission lines ([O III],
[Ne III], and [Ne V]) are dominated by blueshifted components at similar speeds
to the mini-BALs. The blueshifted components are also detected in some
low-ionization emission lines, such as [O II] $\lambda$3727 and some Balmer
lines (H$\alpha$, H$\beta$, and H$\gamma$), even though their cores are
dominated by narrow ($FWHM_{\rm NEL} = 570\pm40$km s$^{-1}$) or broad
components at the systemic redshift of $z=0.18966\pm0.00006$. The mass flow
rate (230-730$~M_\odot \rm yr^{-1}$) and the kinetic luminosity ($\dot{E}_k
\sim 10^{43.6-44.8} $erg s$^{-1}$) are then inferred jointly from the
blueshifted emission and absorption lines. In the NIR spectrum of F11119+3257,
we also find that the Paschen emission lines are unique, in which a very narrow
($FWHM=260\pm20~$km s$^{-1}$) component is shown in only Pa$\alpha$. This
narrow component most probably comes from heavily obscured star formation.
Based on the Pa$\alpha$ and Pa$\beta$ emissions, we obtain an extinction at the
$H$ band, $A_H~>~2.1$ (or a reddenning of $E_{B-V}~>~$3.7), and a star
formation rate of $SFR~>~130\rm M_\odot yr^{-1}$ that resembles the estimates
inferred from the FIR emissions ($SFR_{\rm FIR} = 190\pm90$ $M_\odot$
yr$^{-1}$).